How to Keep Your Dog Hydrated

To keep your dog hydrated, keep a clean dog water bowl full of fresh water at all times, and wash it every day or two. Add more water on hot days and after exercise, and carry some when you travel.

The Merck Veterinary Manual puts a mammal's daily need at about 44 to 66 mL per kg of body weight. That's roughly two-thirds of an ounce to an ounce per pound, and food supplies part of it.

Healthy dogs are good at judging this for themselves. Merck notes that, given plenty of water, healthy animals regulate their own intake well. Your job is mostly to make sure the water is always there, clean and easy to reach.

How much water does a dog need a day?

Water makes up 60 to 70% of an adult pet's body weight, according to the ASPCA. Merck calls it the most important nutrient, and says clean, fresh water should be available at all times.

Here is Merck's range worked out for a few sizes, at a comfortable room temperature:

Dog's weight	Water a day, all sources
10 lb	About 200–300 mL (¾ to 1¼ cups)
25 lb	About 500–750 mL (2 to 3 cups)
50 lb	About 1–1.5 liters (4 to 6 cups)
80 lb	About 1.6–2.4 liters (7 to 10 cups)

Read it as a guide. Merck says individual dogs vary, and the amount depends on diet, environment, activity level and health. A dog on a warm day, or after a long run, will need more.

Merck is also clear that water shouldn't be restricted for a healthy animal. There's no need to ration the bowl.

Does wet food count toward a dog's water?

Yes, and the difference is large. Merck gives canned pet food a moisture content of 60% to more than 87%. Dry food holds just 3 to 11% water, and semimoist food 25 to 35%.

That's why, as Merck puts it, dogs eating mostly canned food generally drink less than dogs on dry food. A dog on wet food who visits the bowl less often may be getting plenty.

A dog on kibble gets almost all of their water from the bowl, so that bowl matters more.

What about milk and other drinks?

Water stays the everyday drink. Anything else is an occasional extra that adds a little fluid alongside it.

One option is Choolip's Berry Good Milk, a ready-to-drink, lactose-free cow's milk for cats and dogs. It provides taurine, calcium, vitamins D3 and E and omega-3, with added lactase for the milk sugar.

Lactase only handles lactose, so a dog who reacts to dairy protein should skip it. Our guide to can dogs drink milk covers how much is sensible.

What makes a good dog water bowl?

Start with clean. The FDA's Center for Veterinary Medicine advises washing your pet's water bowl every day or two, and food bowls after every meal.

The reason is simple. Dogs carry bacteria in their mouths, and those microbes transfer to the dishes they eat and drink from. The FDA notes they can then make people sick who touch the dish or the pet.

Now for the part that explains the puddle by the bowl. Dogs can't suck water up, because their cheeks don't close far enough to form a seal.

A 2015 study in PNAS filmed 19 dogs drinking. On each lap, the tongue curls backward into a ladle, strikes the water and pulls up a column, and the dog bites down on it.

An older measurement the researchers cite puts a single lap at about 2.5 mL, roughly half a teaspoon.

The same researchers note, dryly, that dogs are messy drinkers who splash themselves and the floor. A washable mat under the bowl saves the floor, and a wide, stable bowl is harder to tip.

More bowls help too. Merck states that multiple water sources encourage drinking. A second bowl on another floor, or by the back door, puts water in reach wherever your dog rests.

Are dog water fountains worth it?

You can try one, but the evidence is thin. A PubMed search turned up no published study measuring whether fountains change how much dogs drink.

The fountain research we found is in cats, and it's mixed, as our guide on how to get a cat to drink more water explains.

If you try a fountain, keep a plain bowl out too while your dog gets used to it, and clean the fountain and change its filter as the maker directs. None of the veterinary sources here gives guidance on bowl material or shape.

How do I keep my dog hydrated in hot weather and after exercise?

The ASPCA advises plenty of fresh, clean water when it's hot or humid outdoors, along with a shady spot and a cool indoor area when it's too hot to be outside.

Go easy on exercise when it's hot, too. The ASPCA warns against over-exercising pets in the heat and suggests keeping them indoors when it's extremely hot.

Near water, bring your own. The ASPCA advises giving fresh water and stopping your dog from drinking from the pool, or swallowing ocean or lake water. Rinse chlorine or salt off their coat after a swim.

And never leave your dog alone in a parked car. The ASPCA says that on a hot day, even with the windows open, a car can become a furnace in no time.

Call your vet promptly if your dog:

• pants heavily or struggles to breathe after heat or exercise, and doesn't settle in a cool spot
• drools heavily, seems weak or dazed, or collapses. If your dog collapses, go straight to a vet
• suddenly drinks much more, or much less, than usual

The first two come from the ASPCA's list of overheating signs. The third matters because Merck names health status as one of the factors that sets how much a dog drinks.

How do I keep my dog hydrated when we travel?

Pack water and a bowl from home. The ASPCA suggests bottled water on trips, because water from an area your dog isn't used to could upset their stomach.

Offer a drink at every stop. For meals, the ASPCA suggests a light meal three to four hours before you leave, and no feeding in a moving vehicle.

Do puppies and active dogs need anything extra?

Puppies need the same thing adults do: fresh water available at all times, which the ASPCA advises for all pets. Expect a bathroom trip soon after a big drink.

Merck lists "after drinking a lot of water" among the times puppies naturally need to go, which is useful timing for how to potty train a puppy.

Do dogs need electrolytes?

A complete and balanced dog food already carries them. AAFCO's nutrient profiles set minimum levels of sodium, potassium and chloride in complete dog foods, for growing and adult dogs alike.

None of the veterinary sources used for this article recommends electrolyte drinks for healthy dogs. The one controlled study we found tested a nutrient-enriched water in 16 small-breed dogs for eight weeks, run by Purina researchers.

Those dogs drank more in total, and their urine became more dilute. That's a single small study. If your dog is losing fluid through illness, that's a question for your vet, not the pet aisle.

Questions dog parents ask

How much water should a dog drink a day?

Merck's range is about 44 to 66 mL per kg of body weight, including water from food. For a 25 lb dog that's roughly 2 to 3 cups.

How often should I clean my dog's water bowl?

Every day or two, according to the FDA's Center for Veterinary Medicine, which also advises washing and drying dishes before you refill them.

Is a water fountain good for dogs?

It can be one of several water sources. We found no published research on whether fountains change how much dogs drink, so keep a plain bowl out as well.

Should I leave water out for my dog all day?

Yes. Merck and the ASPCA both say healthy pets should have fresh water available at all times.

Sources

• Merck Veterinary Manual: Nutritional Requirements of Small Animals
• Merck Veterinary Manual, Pet Owner Version: Puppy Care
• FDA Center for Veterinary Medicine: Think Food, Think Pet Food and Feeding!
• ASPCA: Dog Nutrition Tips
• ASPCA: Hot Weather Safety Tips
• ASPCA: Travel Safety Tips
• AAFCO: Proposed revisions to the AAFCO Dog and Cat Food Nutrient Profiles, Pet Food Committee, 2014
• Gart S et al. Dogs lap using acceleration-driven open pumping. PNAS, 2015
• Zanghi BM, Gardner CL. Total Water Intake and Urine Measures of Hydration in Adult Dogs Drinking Tap Water or a Nutrient-Enriched Water. Frontiers in Veterinary Science, 2018

This article is for general information and is not veterinary advice. Talk to your vet about your own dog — they know the animal in front of them.